diff --git a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/entrypoints.kt b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/entrypoints.kt
index 4c279034daa..7ca8a550623 100644
--- a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/entrypoints.kt
+++ b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/entrypoints.kt
@@ -5,15 +5,12 @@ import com.apollographql.apollo.compiler.codegen.SchemaAndOperationsLayout
 import com.apollographql.apollo.compiler.codegen.writeTo
 import com.apollographql.apollo.compiler.internal.DefaultApolloCompilerRegistry
 import com.apollographql.apollo.compiler.internal.GradleCompilerPluginLogger
-import com.apollographql.apollo.compiler.operationoutput.OperationDescriptor
-import com.apollographql.apollo.compiler.operationoutput.OperationId
-import com.apollographql.apollo.compiler.operationoutput.OperationOutput
 import java.io.File
 import java.util.ServiceLoader
 import java.util.function.Consumer
 
 /**
- * EntryPoints contains code that is called using reflection from the Gradle plugin.
+ * EntryPoints contains code called using reflection from the Gradle plugin.
  * This is so that the classloader can be isolated, and we can use our preferred version of
  * Kotlin and other dependencies without risking conflicts.
  *
@@ -160,22 +157,6 @@ class EntryPoints {
   }
 }
 
-@Suppress("DEPRECATION")
-internal fun ApolloCompilerPlugin.toOperationOutputGenerator(): OperationOutputGenerator {
-  return object : OperationOutputGenerator {
-    override fun generate(operationDescriptorList: Collection<OperationDescriptor>): OperationOutput {
-      var operationIds = operationIds(operationDescriptorList.toList())
-      if (operationIds == null) {
-        operationIds = operationDescriptorList.map { OperationId(OperationIdGenerator.Sha256.apply(it.source, it.name), it.name) }
-      }
-      return operationDescriptorList.associateBy { descriptor ->
-        val operationId = operationIds.firstOrNull { it.name == descriptor.name } ?: error("No id found for operation ${descriptor.name}")
-        operationId.id
-      }
-    }
-  }
-}
-
 internal fun Consumer<String>.toLogger(): ApolloCompiler.Logger {
   return object : ApolloCompiler.Logger {
     override fun warning(message: String) {
diff --git a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/internal/legacy.kt b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/internal/legacy.kt
index 8875c1c88c1..aa650a5bcfd 100644
--- a/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/internal/legacy.kt
+++ b/libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/internal/legacy.kt
@@ -13,7 +13,7 @@ import com.apollographql.apollo.compiler.operationoutput.OperationId
 internal class LegacyOperationIdsGenerator(private val plugin: ApolloCompilerPlugin) : OperationIdsGenerator {
   override fun generate(operationDescriptors: List<OperationDescriptor>): List<OperationId> {
     @Suppress("DEPRECATION")
-    val operationIds = plugin.operationIds(operationDescriptors.toList())
+    val operationIds = plugin.operationIds(operationDescriptors)
     if (operationIds != null) {
       println("Apollo: using ApolloCompiler.operationIds() is deprecated. Please use registry.registerOperationIdsGenerator() from beforeCompilationStep() instead.")
       return operationIds